msem-instigator

When Journeying Packmaster enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you didn't put that card onto the battlefield, draw a card.

Vigilance

When Joyful Deviant enters or dies, it deals 1 damage to any target.

As Joyous Chromatelk enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.
{T}: Add one mana of the chosen color.

Whenever a land you control enters, create a 1/1 colorless Servo artifact creature token.
{4}{G}{W}: Put a +1/+1 counter on each creature you control. They gain trample until end of turn.

Concord — This spell costs {2} less to cast if there are four or more card types among permanents you control.
Vigilance (Attacking doesn't cause this creature to tap.)

Once each turn for each card type, when you cast a spell with that type, you may copy it. You may choose new targets for the copy. If it's a permanent spell, the copy gains haste and “At the beginning of the end step, sacrifice this permanent.”
Whenever a permanent you control dies, it deals 1 damage to each opponent.

Archive 3 (As this enters, shuffle the top three cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, you exile up to one target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

[+2]: Exile another target permanent, then return it to the battlefield under its owner's control.
[–2]: Gain control of target creature unless its controller pays its mana cost.
[–5]: You get an emblem with “If a nonland permanent would enter and it wasn't cast, it you control enters instead.”

Double strike, menace, trample
At the beginning of your end step, sacrifice Juddering Mishap unless you've cast a spell with no creature types this turn. (Noncreature spells have no creature types.)

When Judge of Clans enters, adjudicate. (Create a white enchantment Aura token with enchant creature and “Sacrifice this token: Untap enchanted creature.” attached to target creature.)
{T}: Add one mana of any color.

Flying
Whenever Judge of Mahara or another creature you control leaves the battlefield, you gain 2 life.

Flash
Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Judge's Decree enters, exile another target spell or nonland permanent. When Judge's Decree is no longer on the battlefield, the exiled card's owner may cast that card without paying its mana cost.

Noncreature spells your opponents cast cost {1} more to cast for each counter on Judges of Bearidge.
{5}{W}{U}: Put a +1/+1 counter on Judges of Bearidge, then detain each creature with lesser power. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Flying
Concord — When Judicious Djinni enters, if there are four or more card types among permanents you control, return target instant or sorcery card from your graveyard to your hand.

When Jumbo Shrimp enters or when you cycle it, destroy target noncreature permanent.
Cycling {3}{G}{G} ({3}{G}{G}, Discard this card: Draw a card.)

Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{1}, {T}: Choose a nonland card name. Reveal the top three cards of your library and put each revealed card with that name into your hand. Put the rest into your graveyard.

At the beginning of each player's upkeep, that player may sacrifice a creature. If they don't, they discard a card.

Menace
Swampcycling {1}, forestcycling {1} ({1}, Discard this card: Search your libary for a Swamp or Forest card, reveal it, put it into your hand, then shuffle.)

{1}{R}: Exile the top card of your library. If it's a creature card, you may play it until the end of your next turn.
{4}{W}: Put two +1/+1 counters on target creature.

Jungle Hollow enters tapped.
When Jungle Hollow enters, you gain 1 life.
{T}: Add {B} or {G}.

Jungle Shrine enters tapped.
{T}: Add {R}, {G}, or {W}.

When Junktrawler enters, create a tapped colorless Powercell artifact token with “{T}: Add {C}.”
Tap another untapped artifact you control: Junktrawler gets +1/+1 until end of turn.

Flash
Flying
When Justiciar Overseer enters, the next 2 damage that a source of your choice would deal to you and/or permanents you control this turn is dealt to any target instead.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Jutou enters with X +1/+1 counters on her.
{3}{G}: Demigod — You gain life equal to the greatest power among creatures you control.
{6}{G}: God — Search your library for a creature card with the same power as a creature you control, put it onto the battlefield, then shuffle.